Cisco VOIP Basics – Call Broadcast for Cisco CME

This is the fourth and final part of my Cisco voip basics series. ( Parts 1, 2 & 3 ) Our goal in this series has been setting up a working voice gateway that you could use in your home office. In this post were going to cover a very specific issue. How do you ring yours FXS line(s) and your ephone-dns’s?

You can’t

As it turns out, in CME, you can’t do it. I’ve looked everywhere I can think of for an answer to this and have found that CME is lacking in features. At least on the platform that I’ve been using for this tutorial. Here is what I’ve tried.

Configure FXS as SCCP controlled port using STCAPP. This is not supported on my 1760-V for some reason, it appears to be supported on the newer ISRs.

Configure a hunt-group in broadcast mode between the FXS and ephone-dn. I have no clue how to do this, and can’t find any docs that show examples. (All the hunt groups I see are between ephones.. not FXS ports, or even mixed between them)

What I originally tried was just setting the same number/destination-prefix on both, this didn’t work at all. Probably obvious for anyone that does this stuff day to day..

TCL to the rescue

No, I didn’t give up. I actually found a very helpful member of the Cisco Support Community that gave me a copy of a script he had written to support exactly this. You’ll want to download a copy of the script and tftp it over to your router.

Setting the script up is done in a few stages, first we need to define the application, and the parameters we pass to it. We’re going to use 50 for my ephone-dn and 55 for the FXS port.

The next thing we need to do is define the dial-peer that uses the broadcast service from the script. Here, were going to use dial-peer 100 to do just that. We also need to point this towards our FXO port connected to our external phone line.

Thats it! Our bcast TCL script has been configured, and our router is ready to use it. But of course, we’re not quite done yet.

Other issues…

One thing you’ll also need to configure is Private-line automatic ringdown or PLAR. PLAR normally ensures that when a device is taken off-hook, it applies a ringing voltage to the circuit. This is where we get into the realm of things I really don’t understand, or care to research in VOIP. All I know is that setting up connection plar on my FXO port allowed my other phones to stop ringing when I answered.. The full config for my FXO looks something like this.

Another issue with my configuration is that my FXO cards do not support Caller ID, this is the main reason that I have discontinued using my CME server until I feel the need to purchase a new FXO card. In order to support caller id, you’ll need to purchase one of the following cards VIC-2FXO-M1, VIC-2FXO-M2, or the VIC-4FXO-M1.

Final Config.

This is more or less the configuration that I’ve ended up with after my adventure to understand more about Cisco VOIP and setup a working phone system for my home office.

Obviously, as always, if you have any questions please leave a comment below. I promise I’ll try my best to help you out, or at least point you in the right direction. I’m in no way a voice engineer, but I was at least able to make this work for my home office.

Network engineer turned management currently servicing the enterprise data center market. I started working on networks in the ’90s and still feel like that was just a few years ago. Jack of all trades, master of none; I love to learn about everything. Feel free to ask me about photography, woodworking, nhra, watches, or even networking! — For feedback, please leave a comment on the article in question, and I’ll respond as soon as I can. For everything else including fan mail or death threats, contact me via twitter.